diff --git a/package.json b/package.json
index e340942..b6234dd 100644
--- a/package.json
+++ b/package.json
@@ -84,7 +84,7 @@
     "babel-plugin-transform-remove-console": "6.9.4",
     "babel-plugin-unassert": "3.2.0",
     "babel-preset-power-assert": "3.0.0",
-    "c8": "8.0.1",
+    "c8": "9.1.0",
     "esdoc": "1.1.0",
     "esdoc-ecmascript-proposal-plugin": "1.0.0",
     "esdoc-inject-script-plugin": "1.0.0",
diff --git a/yarn.lock b/yarn.lock
index 5d5bfeb..7659bd0 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3397,19 +3397,18 @@ bundle-name@^3.0.0:
   dependencies:
     run-applescript "^5.0.0"
 
-c8@8.0.1:
-  version "8.0.1"
-  resolved "https://registry.yarnpkg.com/c8/-/c8-8.0.1.tgz#bafd60be680e66c5530ee69f621e45b1364af9fd"
-  integrity sha512-EINpopxZNH1mETuI0DzRA4MZpAUH+IFiRhnmFD3vFr3vdrgxqi3VfE3KL0AIL+zDq8rC9bZqwM/VDmmoe04y7w==
+c8@9.1.0:
+  version "9.1.0"
+  resolved "https://registry.yarnpkg.com/c8/-/c8-9.1.0.tgz#0e57ba3ab9e5960ab1d650b4a86f71e53cb68112"
+  integrity sha512-mBWcT5iqNir1zIkzSPyI3NCR9EZCVI3WUD+AVO17MVWTSFNyUueXE82qTeampNtTr+ilN/5Ua3j24LgbCKjDVg==
   dependencies:
     "@bcoe/v8-coverage" "^0.2.3"
     "@istanbuljs/schema" "^0.1.3"
     find-up "^5.0.0"
-    foreground-child "^2.0.0"
+    foreground-child "^3.1.1"
     istanbul-lib-coverage "^3.2.0"
     istanbul-lib-report "^3.0.1"
     istanbul-reports "^3.1.6"
-    rimraf "^3.0.2"
     test-exclude "^6.0.0"
     v8-to-istanbul "^9.0.0"
     yargs "^17.7.2"
@@ -5547,13 +5546,13 @@ flatted@^3.1.0:
   resolved "https://registry.yarnpkg.com/flatted/-/flatted-3.2.7.tgz#609f39207cb614b89d0765b477cb2d437fbf9787"
   integrity sha512-5nqDSxl8nn5BSNxyR3n4I6eDmbolI6WT+QqR547RwxQapgjQBmtktdP+HTBb/a/zLsbzERTONyUB5pefh5TtjQ==
 
-foreground-child@^2.0.0:
-  version "2.0.0"
-  resolved "https://registry.yarnpkg.com/foreground-child/-/foreground-child-2.0.0.tgz#71b32800c9f15aa8f2f83f4a6bd9bff35d861a53"
-  integrity sha512-dCIq9FpEcyQyXKCkyzmlPTFNgrCzPudOe+mhvJU5zAtlBnGVy2yKxtfsxK2tQBThwq225jcvBjpw1Gr40uzZCA==
+foreground-child@^3.1.1:
+  version "3.1.1"
+  resolved "https://registry.yarnpkg.com/foreground-child/-/foreground-child-3.1.1.tgz#1d173e776d75d2772fed08efe4a0de1ea1b12d0d"
+  integrity sha512-TMKDUnIte6bfb5nWv7V/caI169OHgvwjb7V4WkeUvbQQdjr5rWKqHFiKWb/fcOwB+CzBT+qbWjvj+DVwRskpIg==
   dependencies:
     cross-spawn "^7.0.0"
-    signal-exit "^3.0.2"
+    signal-exit "^4.0.1"
 
 forever-agent@~0.6.1:
   version "0.6.1"